Uterine blood flow, calf, and placental weights from beef cows supplemented during late gestation
Maternal nutrition impacts uterine blood flow (BF), thus offspring development. This study’s objective was to investigate the effects of supplementing dried distiller’s grains with solubles (DDGS) during late gestation on uterine BF, calf and placental weights. Multiparous beef cows were randomly divided into a control group (CON; n=15) consuming a diet containing 90% corn stover and 10% corn silage (DM basis) ad libitum and a treatment group (TRT; n = 12) consuming the same diet and DDGS (0.3% BW). Corn silage inclusion was increased to 30% as gestation progressed. Intake was monitored and controlled via Insentec roughage feeders. Ipsilateral and contralateral uterine BF and cross sectional area (CSA) at the bifurcation of each uterine artery was measured by Doppler ultrasonography on d 180, 216, and 246 of pregnancy. At parturition calves and placentas were weighed. Data analysis utilized the mixed procedure in SAS. Contralateral uterine artery BF and CSA increased (P < 0.01) as gestation advanced. For ipsilateral uterine artery BF and CSA, there was a treatment by day of gestation interaction (P < 0.05). CSA was similar (P = 0.30) on d 181, but was greater (P ≤ 0.02) in TRT vs CON cows on d 216 and 246 (0.94 vs 0.71 ± 0.07 cm2 and 1.14 vs 0.76 ± 0.07 cm2, respectively). Ipsilateral BF tended to be greater (P = 0.06) on d 181 in TRT cows compared to CON (11.4 vs 8.2 ± 1.1 L/min), and was greater on d 216 and 246 (21.1 vs 15.4 ± 1.8 and 32.6 vs 19.6 ± 2.7 L/min, respectively). There was no treatment by day interaction (P = 0.17) for total uterine BF, but there was a main effect of treatment (P = 0.02) and day (P < 0.01). DDGS cows had increased uterine BF compared to CON (25.5 vs 19.1 ± 1.8 L/min). Total uterine BF increased (P < 0.01) as gestation advanced (12.2, 22.2, 32.7 ± 2.2 L/min for d 181, 216 and 246). While there was no effect of treatment on gestation length (P = 0.43) or placental weights (P ≥ 0.22), there was a tendency (P= 0.06) for calves born to TRT cows to be heavier (43.3 vs 40.5 ± 1.0 kg). Supplementation with DDGS increased uterine BF which contrasts our previous study; protein and caloric intake differences between these studies is currently under investigation.
Keywords: beef cow, pregnancy, uterine blood flow